Single phase fault isolation and restoration for power distribution network

ABSTRACT

A method for controlling a power distribution network includes receiving, by an electronic processor, a fault indication associated with a fault in the power distribution network from a first isolation device of a plurality of isolation devices. The processor identifies a first subset of a plurality of phases associated with the fault indication and a second subset of the plurality of phases not associated with the fault indication. The first and second subsets each include at least one member. The processor identifies an upstream isolation device upstream of the fault. The processor identifies a downstream isolation device downstream of the fault. The processor sends an open command to the downstream isolation device for each phase in the first subset. Responsive to the first isolation device not being the upstream isolation device, the processor sends a close command to the first isolation device for each phase in the first subset.

FIELD OF DISCLOSURE

Embodiments described herein relate to power distribution networks. Moreparticularly, embodiments described herein relate to systems and methodsfor providing single phase fault isolation and restoration in a powerdistribution network.

SUMMARY

Power distribution networks include fault monitoring equipment thatidentifies problems in the system and opens isolation devices to isolatethe problems. Example problems with the distribution system includeovercurrent faults, phase-to-phase faults, ground faults, etc. that mayarise from various causes, such as equipment failure, weather-relateddamage to equipment, etc. Switching equipment is provided in the powerdistribution network to isolate the detected faults. In some instances,a fault may be detected by an isolation device that is not locatedclosest to the fault. As a result, power may be interrupted for morecustomers than necessary. Various isolation devices attempt to recloseto restore power to non-affected portions of the power distributionnetwork. Power distribution networks typically use three-phasetransmission lines, and the isolation devices are controlled to isolateall three phases in response to a detected fault. Even in cases where aparticular fault only involves one or two of the phases, power isinterrupted for all customers on the affected transmission line.

In particular, embodiments described herein provide systems and methodsfor providing single phase fault isolation and restoration in a powerdistribution network.

In one embodiment, a system for controlling a power distribution networkproviding power using a plurality of phases includes an electronicprocessor and memory storing instructions that, when executed by theelectronic processor, cause the system to receive a first faultindication associated with a fault in the power distribution networkfrom a first isolation device of a plurality of isolation devices. Theelectronic processor identifies a first subset of the plurality ofphases associated with the first fault indication and a second subset ofthe plurality of phases not associated with the first fault indication.The first subset and the second subset each include at least one member.The electronic processor identifies an upstream isolation deviceupstream of the fault. The electronic processor identifies a downstreamisolation device downstream of the fault. The electronic processor sendsan open command to the downstream isolation device for each phase in thefirst subset. Responsive to the first isolation device not being theupstream isolation device, the electronic processor sends a closecommand to the first isolation device for each phase in the firstsubset.

In another embodiment, a method for controlling a power distributionnetwork providing power using a plurality of phases includes receiving,by an electronic processor, a first fault indication associated with afault in the power distribution network from a first isolation device ofa plurality of isolation devices. A first subset of the plurality ofphases associated with the first fault indication and a second subset ofthe plurality of phases not associated with the first fault indicationare identified by the electronic processor. The first subset and thesecond subset each include at least one member. An upstream isolationdevice upstream of the fault is identified by the electronic processor.A downstream isolation device downstream of the fault is identified bythe electronic processor. An open command is sent by the electronicprocessor to the downstream isolation device for each phase in the firstsubset. Responsive to the first isolation device not being the upstreamisolation device, a close command is sent by the electronic processor tothe first isolation device for each phase in the first subset.

Other aspects of the disclosure will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of a system for controlling singlephase fault isolation in a power distribution network, according to someembodiments.

FIG. 2 is a simplified diagram of a power distribution network,according to some embodiments.

FIG. 3 is a diagram of a switchgear system including an isolationdevice, according to some embodiments.

FIGS. 4A-4F are diagrams illustrating the operation of the system ofFIG. 1 for a fault, according to some embodiments.

FIG. 5 is a flowchart of a method for operating the system of FIG. 1 fora fault, according to some embodiments.

FIGS. 6A-6E are diagrams illustrating the operation of the system ofFIG. 1 for a loss of voltage fault, according to some embodiments.

FIG. 7 is a flowchart of a method for operating the system of FIG. 1 fora loss of voltage fault, according to some embodiments.

DETAILED DESCRIPTION

One or more embodiments are described and illustrated in the followingdescription and accompanying drawings. These embodiments are not limitedto the specific details provided herein and may be modified in variousways. Furthermore, other embodiments may exist that are not describedherein. Also, the functionality described herein as being performed byone component may be performed by multiple components in a distributedmanner. Likewise, functionality performed by multiple components may beconsolidated and performed by a single component. Similarly, a componentdescribed as performing particular functionality may also performadditional functionality not described herein. For example, a device orstructure that is “configured” in a certain way is configured in atleast that way, but may also be configured in ways that are not listed.Furthermore, some embodiments described herein may include one or moreelectronic processors configured to perform the described functionalityby executing instructions stored in non-transitory, computer-readablemedium. Similarly, embodiments described herein may be implemented asnon-transitory, computer-readable medium storing instructions executableby one or more electronic processors to perform the describedfunctionality. As used herein, “non-transitory computer-readable medium”comprises all computer-readable media but does not consist of atransitory, propagating signal. Accordingly, non-transitorycomputer-readable medium may include, for example, a hard disk, aCD-ROM, an optical storage device, a magnetic storage device, a ROM(Read Only Memory), a RAM (Random Access Memory), register memory, aprocessor cache, or any combination thereof.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. For example, the useof “including,” “containing,” “comprising,” “having,” and variationsthereof herein is meant to encompass the items listed thereafter andequivalents thereof as well as additional items. The terms “connected”and “coupled” are used broadly and encompass both direct and indirectconnecting and coupling. Further, “connected” and “coupled” are notrestricted to physical or mechanical connections or couplings and caninclude electrical connections or couplings, whether direct or indirect.In addition, electronic communications and notifications may beperformed using wired connections, wireless connections, or acombination thereof and may be transmitted directly or through one ormore intermediary devices over various types of networks, communicationchannels, and connections. Moreover, relational terms such as first andsecond, top and bottom, and the like may be used herein solely todistinguish one entity or action from another entity or action withoutnecessarily requiring or implying any actual such relationship or orderbetween such entities or actions.

FIG. 1 illustrates a system 100 for controlling a power distributionnetwork 105, according to some embodiments. In the example shown, thesystem 100 includes a server 110 communicating with entities in thepower distribution network 105 over one or more communication networks115. In some embodiments, the system 100 includes fewer, additional, ordifferent components than illustrated in FIG. 1. For example, the system100 may include multiple servers 110. The communication network 115employs one or more wired or wireless communication entities. Portionsof the communication network 115 may be implemented using a wide areanetwork, such as the Internet, a local area network, such as aBluetooth™ network or Wi-Fi, and combinations or derivatives thereof. Insome embodiments, components of the system 100 communicate through oneor more intermediary devices not illustrated in FIG. 1.

The server 110 is a computing device that may serve as a centralizedresource for controlling entities in the power distribution network 105.As illustrated in FIG. 1, the server 110 includes an electronicprocessor 120, a memory 125, and a communication interface 130. Theelectronic processor 120, the memory 125 and the communication interface130 communicate wirelessly, over one or more communication lines orbuses, or a combination thereof. The server 110 may include additionalcomponents than those illustrated in FIG. 1 in various configurations.The server 110 may also perform additional functionality other than thefunctionality described herein. Also, the functionality described hereinas being performed by the server 110 may be distributed among multipledevices, such as multiple servers included in a cloud serviceenvironment.

The electronic processor 120 includes a microprocessor, anapplication-specific integrated circuit (ASIC), or another suitableelectronic device for processing data. The memory 125 includes anon-transitory computer-readable medium, such as read-only memory (ROM),random access memory (RAM) (for example, dynamic RAM (DRAM), synchronousDRAM (SDRAM), and the like), electrically erasable programmableread-only memory (EEPROM), flash memory, a hard disk, a secure digital(SD) card, another suitable memory device, or a combination thereof. Theelectronic processor 120 is configured to access and executecomputer-readable instructions (“software”) stored in the memory 125.The software may include firmware, one or more applications, programdata, filters, rules, one or more program modules, and other executableinstructions. For example, the software may include instructions andassociated data for performing a set of functions, including the methodsdescribed herein. For example, as illustrated in FIG. 1, the memory 125may store instructions for executing a fault location, isolation, andrestoration (FLISR) unit 135 to control entities in the powerdistribution network 105.

The communication interface 130 allows the server 110 to communicatewith devices external to the server 110. For example, as illustrated inFIG. 1, the server 110 may communicate with entities in the powerdistribution network 105. The communication interface 130 may include aport for receiving a wired connection to an external device (forexample, a universal serial bus (USB) cable and the like), a transceiverfor establishing a wireless connection to an external device (forexample, over one or more communication networks 115, such as theInternet, local area network (LAN), a wide area network (WAN), and thelike), or a combination thereof.

FIG. 2 is a simplified diagram of the power distribution network 105,according to some embodiments. In the example shown, the powerdistribution network 105 comprises sources, S1-S3, and isolation devicesR1-R14. The sources S1-S3 and isolation devices R1-R14 are connected bytransmission lines 200. In general, the isolation devices R1-R14 serveto segment the power distribution network 105 such that power isprovided via a single source S1-S3 and to isolate portions of the powerdistribution network 105 in response to identified faults. The isolationdevices R1-R14 may also be referred to as reclosers. Open transmissionlines 200 are illustrated with dashed lines, where an open diamond isadjacent the isolation device 305 isolating the transmission line 200from a power source. In general, only one source S1-S3 feeds a sectionof the power distribution network 105. Certain isolation devices R1-R14are designated as tie-in devices that allow a different source S1-S3 tobe tied in to a section normally fed by a different source S1-S3. Forexample, the source S2 feeds the transmission lines 200 associated withthe isolation devices R5, R14, R13, R12. The isolation device R12 is inan open state, and is a tie-in device that may be closed to providepower from one of the other sources S1, S3. Similarly, isolation devicesR7, R9 are tie-in devices associated with the source S1. FIG. 2illustrates the normal operating configuration of the power distributionnetwork 105 with no faults.

FIG. 3 is a diagram of a switchgear system 300 including an isolationdevice 305, according to some embodiments. The isolation device 305 mayalso be referred to as a recloser and corresponds to one of theisolation devices R1-R14 in FIG. 2. In the example provided in FIG. 3,the isolation device 305 receives high voltage electrical power via aline connection 310, and delivers the high voltage electrical power viaa load connection 315. An interrupting medium 320 (for example, a vacuuminterrupter) is electrically coupled between the line connection 310 andthe load connection 315 to selectively interrupt current flowtherebetween. The switchgear system 300 also includes a junction board325 that is electrically coupled to the isolation device 305. Acontroller 330 is electrically coupled to the junction board 325 via acontrol cable 335. In FIG. 3, only one phase of the isolation device 305is illustrated. For ease of description, the other two phases of thethree phase isolation device 305 are not shown or described in detail.However, the other two phases of the three phase isolation device 305may include similar components as shown in FIG. 3. For example, each ofthe other two phases may include an interrupting medium, line and loadconnections, and a junction board. The controller 330 may be connectedto control all of the junction boards 325.

The isolation device 305 automatically tests the electrical line toidentify a fault condition, and automatically opens the line if a faultis detected. In some embodiments, the isolation device 305 opens allthree phases in response to detecting a fault, such as an overcurrentfault. The isolation device 305 may operate in a recloser mode or a oneshot mode.

In the recloser mode, the isolation device 305 determines whether thefault condition was only temporary and has resolved and automaticallyresets to close the line and restore electric power. Many troubleconditions on high voltage lines are temporary (e.g., lightning,windblown tree branches, windblown transmission lines, animals, etc.),and will, by their very nature, remove themselves from the transmissionline if the power is shut off before permanent damage occurs. Theisolation device 305 senses when trouble occurs and automatically opensto remove power. After a short time delay, which may be recognized as alightbulb flicker, for example, the isolation device 305 recloses torestore power. However, if the trouble condition is still present, theisolation device 305 will open again. If the trouble condition persistsfor a predetermined number of times (e.g., three), the isolation device305 locks opens and sends a fault notification via the controller 330 toa centralized controller, such as the FLISR unit 135 executing on theserver 110 of FIG. 1. Examples of permanent problem conditions includedamaged or down transmission lines, equipment failure, equipment damagecaused by lightning strikes, fallen tree limbs, or vehicle crashes, etc.

In the one shot mode, the automatic recloser functionality of theisolation device 305 is disabled. If a fault condition is identified,the isolation device 305 locks open and sends a fault indication via thecontroller 330 without attempting to reclose.

Referring to FIGS. 4A-4F and FIG. 5, the operation of the system of FIG.1 is illustrated for a fault. FIGS. 4A-4F are diagrams illustrating theoperation of the system of FIG. 1 for a fault in a portion of the powerdistribution network 105 of FIG. 2, according to some embodiments. FIG.5 is a flowchart of a method 500 for operating of the system of FIG. 1for a fault, according to some embodiments.

In some embodiments, a lockout fault is a fault condition that causesthe isolation device 305 identifying the condition to lock in an openstate. Example lockout fault conditions include voltage faults, phase tophase faults, ground faults, etc. In some embodiments, the isolationdevice 305 signals a fault indication to the FLISR unit 135 of FIG. 1after attempting to reclose a predetermined number of times, asdescribed above.

In some instances, the isolation device 305 that opens or trips is notthe isolation device 305 closest to the fault. For example, thecommunication links between the isolation devices 305 and the FLISR unit135 may have different latencies. For purposes of the following example,assume that a phase to phase fault is present between the R14 isolationdevice 305 and the R13 isolation device 305. FIG. 4A illustrates thepower distribution network 105 prior to any automatic operations, withthe fault illustrated between the R14 and R13 isolation devices 305.

In response to the fault, the R5 isolation device 305 locks open andsends a fault indication (i.e., as indicated by the “!” in the R5block). Referring to FIG. 5, a fault indication is received in the FLISRunit 135 (block 505), for example, from the R5 isolation device 305. Insome embodiments, the FLISR unit 135 waits for a predetermined timeinterval (e.g., XX seconds) after receiving the fault indication beforeproceeding with restoration operations. As shown in FIG. 4B, the R5isolation device 305 is locked open for a first subset of the phasesthat includes the faulted phases, B and C. A second subset of the phasesincludes the non-faulted phase, A.

After receiving fault indication (block 505), the FLISR unit 135attempts to identify the fault location by examining the fault states ofother isolation devices downstream of the fault issuing R5 isolationdevice 305. Isolation devices 305 with asserted faults states areidentified with “!” indicators, and isolation devices 305 with clearfault states are identified with “-” indicators in FIG. 4B. In someembodiments, the isolation devices 305 send fault states at periodictime intervals, immediately in response to certain events, or inresponse to a refresh query from the FLISR unit 135.

As shown in block 510, the FLISR unit 135 identifies an upstreamisolation device 305 representing the isolation device 305 immediatelyupstream of the fault, and as shown in block 515, the FLISR unit 135identifies a downstream isolation device 305 representing the isolationdevice 305 immediately downstream of the fault. In the example of FIG.4B, the R14 isolation device 305 is the upstream isolation device 305,and the R13 isolation device 305 is the downstream isolation device 305.In general, the isolation devices 305 downstream of the R5 isolationdevice 305, but before the fault, should have the same fault state asthe R5 isolation device 305. The isolation device 305 immediatelydownstream of the fault should have a fault state that is clear sincethe fault does not affect the transmission lines associated with thatisolation device 305. In some embodiments, the isolation device 305 thatlocks out and generates the fault indication is also the downstreamisolation device 305. The FLISR unit 135 identifies the isolation device305 furthest downstream in a string of isolation devices 305 having afault state that matches the fault state of the triggering R5 isolationdevice 305 as the upstream isolation device (i.e., the R14 isolationdevice 305) (block 510). The FLISR unit 135 identifies the isolationdevice 305 downstream of the R14 upstream isolation device 305 having afault state that does not register the fault seen by the triggering R5isolation device as the downstream isolation device 305 (i.e., the R13isolation device 305).

As shown in block 520, the FLISR unit 135 identifies a fault mismatch. Afault mismatch is registered in response to an isolation device 305downstream of the triggering R5 isolation device 305 having a faultstate that registers a different fault condition than the fault state ofthe triggering isolation device 305. For example, a mismatch may beidentified in an example where the triggering isolation device 305registers a phase to phase fault affecting phases B and C, and one ofthe downstream isolation devices 305 registers a fault with phase A.Although block 520 is illustrated as being performed after block 515,the mismatch condition is actually identified concurrently with theidentification of the upstream isolation device 305 (block 510) and theidentification of the downstream isolation device 305 (block 515). If afault mismatch is identified (block 520), the FLISR unit 135 opens allphases of the isolation device 305 prior to the fault mismatch as shownin block 525 and proceeds with three phase restoration. If a faultmismatch is not identified (block 520), the FLISR unit 135 proceeds withsingle phase restoration operations.

As shown in block 530, the FLISR unit 135 sends open commands for thefaulted phases in the first subset to the R13 downstream isolationdevice 305, as illustrated in FIG. 4C. In some embodiments, the FLISRunit 135 also sends open commands to the R14 upstream isolation device305 prior to opening the R13 downstream isolation device 305. In aninstance where the isolation device 305 identifying the fault conditionis also the upstream isolation device 305 (i.e., closest to the fault),the isolation device 305 identifying the fault condition is already openfor the faulted states, and an open command need not be sent to theupstream isolation device 305.

As shown in block 535, the FLISR unit 135 sends close commands for thefaulted phases in the first subset to the R5 isolation device 305 thattriggered the fault condition. In an instance where the isolation device305 identifying the fault condition is also the upstream isolationdevice 305 (i.e., closest to the fault), close commands need not be sentto the upstream isolation device 305. Closing the non-faulted phasesrestores power to customers up to the R14 upstream isolation device 305.In some embodiments, when there are multiple non-faulted phases, theFLISR unit 135 closes the non-faulted phases individually usingsequential close commands.

As shown in block 540, the FLISR unit 135 sends close commands for atie-in isolation device 305, as illustrated in FIG. 4E. For example, theR12 isolation device 305 is downstream of the fault and the R13downstream isolation device 305 and can provide power from the sourceS3. In some embodiments, the FLISR unit 135 sends a ganged close commandto the R12 tie-in device 305. In some embodiments, the FLISR unit 135sends mode messages to the R5, R14, R13, R12, R8, R10, R11 isolationdevices 305 on the parallel phases to the alternate source S3 placingthem in one shot mode prior to sending the close commands. Thus, if oneof the isolation devices 305 on the parallel phases trips, automaticreclosing is prevented.

As shown in block 545, the FLISR unit 135 sends open commands to the R13downstream isolation device 305 for the parallel phases (i.e., thephases in the second subset), as illustrated in FIG. 4F. For example,the A phase for the R13 isolation device 305 is fed by both the sourceS2 and the source S3. Opening the non-faulted phase removes thisparallel source condition. In some embodiments, when there are multiplenon-faulted phases in the second subset, the FLISR unit 135 opens thenon-faulted phases on the R13 downstream isolation device 305individually using sequential open commands. In some embodiments, aftercompleting the tie-in processing (block 545) without any trips, theFLISR unit 135 sends mode messages to the R15, R14, R13, R12, R8, R10,and R11 isolation devices 305 on the path to both sources S2, S3 placingthem back in reclose mode.

As shown in block 550, the FLISR unit 135 sends fault state resetcommands to the R5, R14, and R13 isolation devices 305 to reset thefault states and allow fault monitoring to be processed using there-configured the power distribution network 105.

Referring to FIGS. 6A-6E and FIG. 7, the operation of the system of FIG.1 is illustrated for a loss of voltage (LOV) fault. FIGS. 6A-6E arediagrams illustrating the operation of the system of FIG. 1 for an LOVfault in a portion of the power distribution network 105 of FIG. 2,according to some embodiments. FIG. 7 is a flowchart of a method 700 foroperating of the system of FIG. 1 for an LOV fault, according to someembodiments.

In some embodiments, an LOV fault is detected by one or more of theisolation devices 305, but does not cause an automatic lockout or tripof the identifying isolation device 305. An LOV fault is defined as anevent where the measured voltage on at least one phase drops below apredefined threshold level. In some embodiments, the predefinedthreshold level (e.g., 5-95%) is a user-specified parameter.

Referring to FIG. 7, an LOV fault indication is received as shown inblock 705, for example, from the R2 isolation device 305 (i.e., asindicated by the “!” in the R2 block). In some instances, the isolationdevice 305 that identifies the LOV fault is not the isolation device 305closest to the fault. For example, the communication links between theisolation devices 305 and the FLISR unit 135 may have differentlatencies. For purposes of the following example, assume that the LOVfault is present due to a fault between the R4 isolation device 305 andthe R6 isolation device 305 on the A phase, and the R2 isolation device305 identifies the LOV fault responsive to the voltage dropping belowthe predefined threshold. FIG. 6A illustrates the power distributionnetwork 105 prior to any automatic operations, with the faultillustrated on the A phase between the R4 and R6 isolation devices 305.The FLISR unit 135 identifies a first subset of the phases that includesthe faulted phase, A, and a second subset of the phases that includesthe non-faulted phases, B and C.

As shown in block 710, the FLISR unit 135 determines if the LOV fault isassociated with an immediate lockout condition. In some embodiments,immediate lockout conditions include the LOV fault occurring at atransformer or at a substation, indicating an equipment failure. If animmediate lockout condition is identified (block 710), the FLISR unit135 initiates a lockout of all phases of the isolation devices 305closest to the LOV fault as shown in block 715.

As shown in block 720, the FLISR unit 135 determines if the LOV fault isassociated with a concurrent underfrequency event. If a concurrentunderfrequency event is identified, the FLISR unit 135 ignores the LOVevent as shown in block 725.

In some embodiments, the FLISR unit 135 waits for a predetermined timeinterval (e.g., 30 seconds) after receiving the lockout fault indicationbefore proceeding with restoration operations. As shown in block 730,the FLISR unit 135 determines if the LOV fault is still present afterthe predetermined time interval. The FLISR unit 135 may evaluate thecurrently reported fault states or send a refresh command to theisolation devices 305 to evaluate the status of the LOV fault uponexpiration of the timer (block 730). If the LOV fault clears (block730), the FLISR unit 135 ignores the LOV fault as shown in block 725. Ifthe LOV fault is still present (block 730), the FLISR unit 135 attemptsto identify the fault location by examining the fault states of otherisolation devices 305 starting from the source S3 and working toward theLOV fault issuing R2 isolation device 305.

As shown in block 740, the FLISR unit 135 identifies a downstreamisolation device 305 representing the isolation device 305 immediatelydownstream of the LOV fault. The FLISR unit 135 starts at the source S3,and evaluates the fault states of the R11, R10, R8, R7, R6, and R4isolation devices 305. Isolation devices 305 with asserted faults statesare identified with “!” indicators, and isolation devices 305 with clearfault states are identified with “-” indicators in FIG. 6B. In theexample of FIG. 6B, the R6 isolation device 305 is the last isolationdevice 305 with a clear fault state, and the R4 isolation device 305 isthe downstream isolation device 305, as it is the first with an assertedLOV fault state. In general, the isolation devices 305 downstream of thefault, e.g., the R4, R2, and R3 isolation devices 305, should have thesame asserted LOV fault states, and the R6 isolation device 305immediately upstream of the fault should have a LOV fault state that isclear since the fault does not affect the transmission lines associatedwith the R6 isolation device 305. The FLISR unit 135 identifies theisolation device 305 downstream of the R6 isolation device 305 with anasserted LOV fault state as the downstream isolation device 305 (i.e.,the R4 isolation device 305) (block 740).

As shown in block 745, the FLISR unit 135 identifies a fault mismatch. Afault mismatch is registered in response to the R4 isolation device 305having a fault state that registers a different LOV fault condition thanthe fault state of the R2 triggering isolation device 305. For example,a mismatch may be identified in an example where the R4 isolation device305 registers an LOV affecting phase A, and the R2 triggering isolationdevices 305 registers an LOV fault with a different phase. Althoughblock 745 is illustrated as being performed after block 740, themismatch condition is actually identified concurrently with theidentification of the downstream isolation device 305 (block 740). If afault mismatch is identified (block 745), the FLISR unit 135 opens allphases of the isolation device 305 with the fault mismatch as shown inblock 750. If a fault mismatch is not identified (block 745), the FLISRunit 135 proceeds with single phase isolation and restorationoperations.

As shown in block 755, the FLISR unit 135 sends open commands for thephases in the first subset affected by the LOV fault (i.e., the A phase)to the R4 downstream isolation device 305, as illustrated in FIG. 6C.Open transmission lines 200 are illustrated with dashed lines, where anopen diamond is adjacent the isolation device 305 isolating thetransmission line 200 from a power source.

As shown in block 760, the FLISR unit 135 sends close commands for atie-in isolation device 305, as illustrated in FIG. 6D. For example, theR9 isolation device 305 is downstream of the fault and the R4 downstreamisolation device 305 and can provide an alternate path for power fromthe source S3. In some embodiments, the FLISR unit 135 sends a gangedclose command to the R9 tie-in device 305. In some embodiments, theFLISR unit 135 sends mode messages to the R10, R8, R6, R7, R11, R9, R3,R2, and R4 isolation devices 305 on the paralleled phase placing them inone shot mode prior to sending the close commands. Thus, if one of theisolation devices 305 on the paralleled phases trips, automaticreclosing is prevented.

As shown in block 765, the FLISR unit 135 sends open commands to the R4downstream isolation device 305 for the parallel phases, as illustratedin FIG. 6E. For example, the non-faulted phases in the second subset(i.e., the B and C phases) for the R4 isolation device 305 are fed bythe source S3 from both sides. Opening the non-faulted phase(s) removesthis parallel source condition. In some embodiments, when there aremultiple non-faulted phases, the FLISR unit 135 opens the non-faultedphases on the R4 downstream isolation device 305 individually usingsequential open commands. In some embodiments, after completing thetie-in processing (block 765) without any trips, the FLISR unit 135sends mode messages to the R7, R6, R4, R3, R2, R8, R10, and R11isolation devices 305 placing them back in reclose mode.

The techniques described herein isolate faults and restore power usingan individual phase approach. This approach increases system utilizationby reducing the number of customers experiencing power outages as aresult from a fault condition, thereby increasing customer satisfactionand preserving revenue generated by the non-affected phases.

The following examples illustrate example systems and methods describedherein.

Example 1: a system for controlling a power distribution networkproviding power using a plurality of phases, the system comprising: anelectronic processor; and memory storing instructions that, whenexecuted by the electronic processor, cause the system to: receive afirst fault indication associated with a fault in the power distributionnetwork from a first isolation device of a plurality of isolationdevices; identify a first subset of the plurality of phases associatedwith the first fault indication and a second subset of the plurality ofphases not associated with the first fault indication, wherein the firstsubset and the second subset each include at least one member; identifyan upstream isolation device upstream of the fault; identify adownstream isolation device downstream of the fault; send an opencommand to the downstream isolation device for each phase in the firstsubset; and responsive to the first isolation device not being theupstream isolation device, send a close command to the first isolationdevice for each phase in the first subset.

Example 2: the system of example 1, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to: responsive to the first isolation device not being theupstream isolation device, sending an open command to the upstreamisolation device for each phase in the first subset.

Example 3. the system of example 1, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to identify the upstream isolation device by: receiving faultstates of the plurality of isolation devices; and designating a firstselected isolation device positioned furthest downstream of a firstsource in the power distribution network having a fault state consistentwith the first fault indication as the upstream isolation device.

Example 4: the system of example 3, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to identify the downstream isolation device by designating asecond selected isolation device positioned downstream of the upstreamisolation device having a fault state that does not indicate the firstfault indication as the downstream isolation device.

Example 5: the system of example 3, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to: identify a second selected isolation device downstream of thefirst isolation device and upstream of the downstream isolation devicehaving a fault state indicating a second fault indication different thanthe first fault indication; and send an open command to the secondselected isolation device for each of the plurality of phases.

Example 6: the system of example 3, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to: receive refreshed fault states of the plurality of isolationdevices after receiving the first fault indication, wherein identifyingthe downstream isolation device and the upstream isolation devicecomprises identifying the downstream isolation device and the upstreamisolation device using the refreshed fault states.

Example 7: the system of example 1, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to: send a close command to the tie-in isolation device for eachof the plurality of phases; and send an open command to the downstreamisolation device for each phase in the second subset.

Example 8: the system of example 7, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to send the close command to the tie-in isolation device bysending a ganged close command to concurrently close all of the phasesof the tie-in isolation device.

Example 9: the system of example 8, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to: send fault state reset commands to the plurality of isolationdevices having asserted fault states after sending the open command tothe tie-in isolation device.

Example 10 The system of example 7, wherein the memory storesinstructions that, when executed by the electronic processor, cause thesystem to: send configuration commands to the tie-in isolation device,the upstream isolation device, and the downstream isolation device todisable a reclosing mode of the tie-in isolation device, the upstreamisolation device, and the downstream isolation device prior to sendingthe close command to the tie-in isolation device; and send configurationcommands to the tie-in isolation device, the upstream isolation device,and the downstream isolation device to enable the reclosing mode of thetie-in isolation device, the upstream isolation device, and thedownstream isolation device after sending the open command to the tie-inisolation device.

Example 11: a method for controlling a power distribution networkproviding power using a plurality of phases, comprising: receiving, byan electronic processor, a first fault indication associated with afault in the power distribution network from a first isolation device ofa plurality of isolation devices; identifying, by the electronicprocessor, a first subset of the plurality of phases associated with thefirst fault indication and a second subset of the plurality of phasesnot associated with the first fault indication, wherein the first subsetand the second subset each include at least one member; identifying, bythe electronic processor, an upstream isolation device upstream of thefault; identifying, by the electronic processor, a downstream isolationdevice downstream of the fault; sending an open command, by theelectronic processor, to the downstream isolation device for each phasein the first subset; and responsive to the first isolation device notbeing the upstream isolation device, sending a close command, by theelectronic processor, to the first isolation device for each phase inthe first subset.

Example 12: the method of example 11, comprising: responsive to thefirst isolation device not being the upstream isolation device, sending,by the electronic processor, an open command to the upstream isolationdevice for each phase in the first subset.

Example 13: the method of example 11, wherein identifying, by theelectronic processor, the upstream isolation device comprises:receiving, by the electronic processor, fault states of the plurality ofisolation devices; and designating, by the electronic processor, a firstselected isolation device positioned furthest downstream of a firstsource in the power distribution network having a fault state consistentwith the first fault indication as the upstream isolation device.

Example 14: the method of example 13, wherein identifying, by theelectronic processor, the downstream isolation device comprisesdesignating, by the electronic processor, a second selected isolationdevice positioned downstream of the upstream isolation device having afault state that does not indicate the first fault indication as thedownstream isolation device.

Example 15: the method of example 13, comprising: identifying, by theelectronic processor, a second selected isolation device downstream ofthe first isolation device and upstream of the downstream isolationdevice having a fault state indicating a second fault indicationdifferent than the first fault indication; and sending an open command,by the electronic processor, to the second selected isolation device foreach of the plurality of phases.

Example 16: the method of example 13, comprising: receiving, by theelectronic processor, refreshed fault states of the plurality ofisolation devices after receiving the first fault indication, whereinidentifying, by the electronic processor, the downstream isolationdevice and the upstream isolation device comprises identifying, by theelectronic processor, the downstream isolation device and the upstreamisolation device using the refreshed fault states.

Example 17: the method of example 11, comprising: sending a closecommand, by the electronic processor, to the tie-in isolation device foreach of the plurality of phases, and the method comprises: and sendingan open command, by the electronic processor, to the tie-in isolationdevice for each phase in the second subset.

Example 18: the method of example 17, wherein sending the close command,by the electronic processor, to the tie-in isolation device comprisessending a ganged close command to concurrently close all of the phasesof the tie-in isolation device.

Example 19: the method of example 17, comprising: sending fault statereset commands, by the electronic processor, to the plurality ofisolation devices having asserted fault states after sending the opencommand to the tie-in isolation device.

Example 20: the method of example 17, comprising: sending configurationcommands, by the electronic processor, to the tie-in isolation device,the upstream isolation device, and the downstream isolation device todisable a reclosing mode of the tie-in isolation device, the upstreamisolation device, and the downstream isolation device prior to sendingthe close command to the tie-in isolation device; and sendingconfiguration commands, by the electronic processor, to the tie-inisolation device, the upstream isolation device, and the downstreamisolation device to enable the reclosing mode of the tie-in isolationdevice, the upstream isolation device, and the downstream isolationdevice after sending the open command to the tie-in isolation device.

Various features and advantages of the embodiments described herein areset forth in the following claims.

What is claimed is:
 1. An isolation device included in a powerdistribution network, the isolation device comprising: an interrupterand an electronic controller configured to: identify the occurrence of afault in the power distribution network; transmit a first faultindication associated with the fault in the power distribution networkto a centralized controller; control the interrupter to open a firstsubset of a plurality of phases associated with the first faultindication; maintain a second subset of the plurality of phases notassociated with the first fault indication in a closed state, whereinthe first subset and the second subset each include at least one member;receive a close command from the centralized controller for each phasein the first subset when the isolation device is a downstream isolationdevice; and maintain each phase in the first subset in an open statewhen the first isolation device is an upstream isolation device.
 2. Theisolation device of claim 1, wherein the electronic controller isfurther configured to transmit a refreshed fault state aftertransmitting the first fault indication.
 3. The isolation device ofclaim 1, wherein the isolation device is a tie-in isolation device. 4.The isolation device of claim 3, wherein the electronic controller isfurther configured to receive a ganged close command to concurrentlyclose all of the phases included in the first subset and the secondsubset.
 5. The isolation device of claim 1, wherein the electroniccontroller is further configured to receive a fault state reset command.6. The isolation device of claim 1, wherein the electronic controller isfurther configured to receive a configuration command to disable areclosing mode of the isolation device.
 7. An isolation device includedin a power distribution network, the isolation device comprising: aninterrupter and an electronic controller configured to: identify theoccurrence of a fault in the power distribution network; transmit afirst fault indication associated with the fault in the powerdistribution network to a centralized controller; control theinterrupter to open a first subset of a plurality of phases associatedwith the first fault indication; maintain a second subset of theplurality of phases not associated with the first fault indication in aclosed state when the second subset includes at least one member;receive a close command from the centralized controller for each phasein the first subset when the isolation device is a downstream isolationdevice; and maintain each phase in the first subset in an open statewhen the first isolation device is an upstream isolation device.
 8. Theisolation device of claim 7, wherein the electronic controller isfurther configured to transmit a refreshed fault state aftertransmitting the first fault indication.
 9. The isolation device ofclaim 7, wherein the isolation device is a tie-in isolation device. 10.The isolation device of claim 9, wherein the electronic controller isfurther configured to receive a ganged close command to concurrentlyclose all of the phases included in the first subset and the secondsubset.
 11. The isolation device of claim 7, wherein the electroniccontroller is further configured to receive a fault state reset command.12. The isolation device of claim 7, wherein the electronic controlleris further configured to receive a configuration command to disable areclosing mode of the isolation device.
 13. A system for controlling apower distribution network providing power using a plurality of phases,the system comprising: an electronic processor configured to: receive afirst fault indication associated with a fault in the power distributionnetwork from a first isolation device of a plurality of isolationdevices; identify a first subset of the plurality of phases associatedwith the first fault indication and a second subset of the plurality ofphases not associated with the first fault indication, wherein the firstsubset includes at least one member; identify an upstream isolationdevice upstream of the fault; identify a downstream isolation devicedownstream of the fault; send an open command to the downstreamisolation device for each phase in the first subset; send a closecommand to the first isolation device for each phase in the first subsetwhen the first isolation device is not the upstream isolation device;and not send a close command to the first isolation device for eachphase in the first subset when the first isolation device is theupstream isolation device.
 14. The system of claim 13, wherein theelectronic processor is configured to: responsive to the first isolationdevice not being the upstream isolation device, send an open command tothe upstream isolation device for each phase in the first subset. 15.The system of claim 13, wherein the electronic processor is configuredto identify the upstream isolation device by: receiving fault states ofthe plurality of isolation devices; and designating a first selectedisolation device positioned furthest downstream of a first source in thepower distribution network having a fault state consistent with thefirst fault indication as the upstream isolation device.
 16. The systemof claim 15, wherein the electronic processor is configured to identifythe downstream isolation device by designating a second selectedisolation device positioned downstream of the upstream isolation devicehaving a fault state that does not indicate the first fault indicationas the downstream isolation device.
 17. The system of claim 15, whereinthe electronic processor is configured to: identify a second selectedisolation device downstream of the first isolation device and upstreamof the downstream isolation device having a fault state indicating asecond fault indication different than the first fault indication; andsend an open command to the second selected isolation device for each ofthe plurality of phases.
 18. The system of claim 15, wherein theelectronic processor is configured to: receive refreshed fault states ofthe plurality of isolation devices after receiving the first faultindication, wherein identifying the downstream isolation device and theupstream isolation device comprises identifying the downstream isolationdevice and the upstream isolation device using the refreshed faultstates.
 19. The system of claim 13, wherein the electronic processor isconfigured to: send a close command to a tie-in isolation device foreach of the plurality of phases; and send an open command to thedownstream isolation device for each phase in the second subset.
 20. Thesystem of claim 19, wherein the electronic processor is configured tosend the close command to the tie-in isolation device by sending aganged close command to concurrently close all of the phases of thetie-in isolation device.